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authorSteven Rostedt <srostedt@redhat.com>2009-09-04 12:35:16 -0400
committerSteven Rostedt <rostedt@goodmis.org>2009-09-04 18:46:51 -0400
commitf633903af2ceb0cec07d45e499a072b6593d0ed1 (patch)
tree9a484fa299142a00d0dbb5a97e1108031db96e70 /kernel/trace
parent2f26ebd549b9ab55ac756b836ec759c11fe93f81 (diff)
tracing: make tracing_reset safe for external use
Reseting the trace buffer without first disabling the buffer and waiting for any writers to complete, can corrupt the ring buffer. This patch makes the external version of tracing_reset safe from corruption by disabling the ring buffer and calling synchronize_sched. This version can no longer be called from interrupt context. But all those callers have been removed. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7daf372e319..0418e2650d4 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -641,13 +641,26 @@ void unregister_tracer(struct tracer *type)
mutex_unlock(&trace_types_lock);
}
-void tracing_reset(struct trace_array *tr, int cpu)
+static void __tracing_reset(struct trace_array *tr, int cpu)
{
ftrace_disable_cpu();
ring_buffer_reset_cpu(tr->buffer, cpu);
ftrace_enable_cpu();
}
+void tracing_reset(struct trace_array *tr, int cpu)
+{
+ struct ring_buffer *buffer = tr->buffer;
+
+ ring_buffer_record_disable(buffer);
+
+ /* Make sure all commits have finished */
+ synchronize_sched();
+ __tracing_reset(tr, cpu);
+
+ ring_buffer_record_enable(buffer);
+}
+
void tracing_reset_online_cpus(struct trace_array *tr)
{
struct ring_buffer *buffer = tr->buffer;
@@ -661,7 +674,7 @@ void tracing_reset_online_cpus(struct trace_array *tr)
tr->time_start = ftrace_now(tr->cpu);
for_each_online_cpu(cpu)
- tracing_reset(tr, cpu);
+ __tracing_reset(tr, cpu);
ring_buffer_record_enable(buffer);
}